Safe tunnelling its a process

SAFE TUNNELLINGIt’s All About Process

Inputs – Process(es) - Output

IDENTIFY & DESIGN PROTECTION WORKS

GEOLOGICAL -GEOTECHNICAL MODELSITE INVESTIGATIONS (All previous data, desk study, other project data.)

BUILDING RISK ASSESSMENTS & PROTECTION PLANS. Allowable Limits of Deformation

ALIGNMENT OF RAIL TRACK & STATION LOCATION

INSTRUMENTATION DESIGN

SETTLEMENT ANALYSISGround loss, shield loss, tailskin loss, sensitivity

TBM OPERATIONAL PARAMETERS & RANGE -Face Pressure, grout pressure/volume

SURVEYS FOR UTILITIES, ID NATURE OF MATERIAL & ALLOWABLE LIMITS OF DEFORMATION

GEOLOGICAL PROFILE & GEOTECHNICAL PARAMETERS

SITE INVESTIGATIONSSupplementary & Instrumentation Installation

BUILDING CONDITION SURVEYS, STRUCTURAL SURVEYS,

Confirm Extent and magnitude of settlement, correctness of face pressure

Confirm /Reassess Geological profile and face pressures required to ensure settlements controlled.

Confirm or Revise Building protection Works as required. Revise risk assessment

MONITORINGTBM Parameters

Face PressureGrout Volume & PressureMuck VolumeThrust, torque & Advance Speed

InstrumentationDrilling Data against geological profilePlanned against actual settlementMonitoring of Treated Areas

Immediate ActionsReading FrequencyAccuracy checksVisual Inspections of surface/buildings

SAFE TUNNELLING

Controlled settlement, minimal impact on infrastructure, optimised face pressures,

controlled progress

CONSTRUCTIONTunnelling

TBM OperationFace pressure,Grouting Volume & PressureMuck VolumeThrustTorqueSpeed of AdvanceSteering / Survey Control

Lining ErectionBuild Quality / ReparsAlignment

Ground TreatmentDrillingGroutingVerification

Immediate ActionsAlarm PlansStandard Operating Procedures

DESIGN OF TUNNEL ADVANCEHorizontal & Vertical Alignment - deeper tunnels have greater pressures, tight curves may require tapered rings

Geotechnical Interpretation - possible geological hazards, mixed face conditions, geological boundariesFace Pressures - control of face pressure to avoid stress relaxation & overexcavation

Weights / Volumes - assessment of weight based on range of in-situ density, assess likely use of soil conditioning Instrument Plan - types & distribution of instruments based on predicted settlements and location of buildings, frequency of reading

Settlement Contours & Settlement Limits - assessment of extent of predicted settlement, allows a check to be carried out during construction

Required Consolidation Works - building protection worked to prevent any adverse effects due to settlement.High Risk Areas, Structures & utilities - indicated on drawings to advise of additional care/reporting

Anticipated Anomalies & Actions - Loss of face pressure, additional grout, overexcavationProbing - predicted geology, tates of penetration

TUNNEL MANAGEMENT PROCESS

DESIGN INPUT

DESIGN PROCESS

DESIGN OUTPUT

CONSTRUCTION INPUT

CONSTRUCTION PROCESS

CONSTRUCTION OUTPUT

Input 'field data' &/ or correction factors into design

TBM -GROUND INTERACTIONCompliance with settlement limits

Compliance with Face Pressure & Grout requirementsCompliance with alignment

DAILY/WEEKLY BASIS REVIEW OF DATA

TBM DesignSegment Design

ALIGNMENT VALIDATION -Wriggle survey

ALIGNMENT VERIFICATION- Track Work Validation

CONFIRM ALIGNMENT - Design modifiaction may be necessary, signalling, route restrictions.

Basic Inputs – Purpose of the Tunnel



DESIGN INPUT

Design Process










DESIGN PROCESS


…and coordination










DESIGN PROCESS


Design to Construction

DESIGN OUTPUT

CONSTRUCTION INPUT

Tunnel Advance – Design to Practice





Required Consolidation Works - building protection worked to prevent any adverse effects due to settlement.High Risk Areas, Structures & utilities- indicated on drawings to advise of additional care/reporting


ConstructionCONSTRUCTIONTunnelling





Monitoring (Can’t manage/control what you don’t measure)





Coordination & Collaboration

SAFE TUNNELLING




Construction Output

SAFE TUNNELLING


controlled progress

Feedback Loops• Alignment – ensure the tunnel is in the correct place and take

necessary actions• Monitoring and actual performance against design assumptions• Change design if required / if possible:opportunities in better ground, increased risk in poorer ground or sub-optimal equipment

selection and workarounds required• Changes in ground and possible claims against any contractual

baseline

Holistic View• Many specialist areas contribute to the tunnel design• Many views and opinions• Many data sources• Lots of data available• Multiple stakeholders along the alignment and through the process• One tunnel!• One error can be enough to be catastrophic!!












Confirm Extent and magnitude of settlement, correctness of face pressure

Confirm /Reassess Geological profile and face pressures required to ensure settlements controlled.

Confirm or Revise Building protection Works as required. Revise risk assessment





SAFE TUNNELLING


controlled progress

CONSTRUCTIONTunnelling









Required Consolidation Works - building protection worked to prevent any adverse effects due to settlement.High Risk Areas, Structures & utilities- indicated on drawings to advise of additional care/reporting


TUNNEL MANAGEMENT PROCESS

DESIGN INPUT

DESIGN PROCESS

DESIGN OUTPUT

CONSTRUCTION INPUT

CONSTRUCTION PROCESS

CONSTRUCTION OUTPUT

Input 'field data' &/ or correction factors into design





ALIGNMENT VALIDATION -Wriggle survey

ALIGNMENT VERIFICATION- Track Work Validation

CONFIRM ALIGNMENT - Design modifiaction may be necessary, signalling, route restrictions.

Safe tunnelling its a process

Engineering

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